How to Install Flarum Forum on Debian 11
Flarum is free and open-source forum software written in PHP, JavaScript, and TypeScript. This tutorial will teach you how to install Flarum on the Debian 11 Bullseye. This tutorial also covers some basic configurations of LAMP Stack and the installation of PHP Composer for the Flarum web application.
Source: Howtoforge Linux Howtos und Tutorials